Steering system for a steerable vehicle

Patent metadata

Field	Value
Publication number	US-10501111-B2
Application number	US-201715461966-A
Country	US
Kind code	B2
Filing date	Mar 17, 2017
Priority date	Mar 18, 2016
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

A steering system for a steerable vehicle includes at least two steerable wheels, to each of which an electrically operable steering actuator to enable the steering actuator to adjust the steering angle of the particular steerable wheel by application of a steering torque. The at least two steering actuators can be mechanically coupled to each other so that, in the event of a failure or a malfunction of the one steering actuator, the steering torque provided by the other steering actuator can be transferred to the one steering actuator, to enable the steering angle of the steerable wheel assigned to the failed steering actuator to still be changed via the other steering actuator. The at least two steering actuators can be mechanically coupled to each other via a bendable shaft or via a universal joint shaft which includes at least two rigid shafts hingedly connected via a universal joint.

First claim

The invention claimed is:

1. A steering system for a steerable vehicle, comprising:
at least two steerable wheels, each of which is connected to an electrically operable steering actuator to enable each electrically operable steering actuator to adjust a steering angle of a steerable wheel by application of a steering torque,
wherein the electrical operable steering actuators are mechanically coupled to each other in such a way that, in the event of a failure or a malfunction of a first steering actuator, the steering torque provided by a second steering actuator is transferred to the first steering actuator, to enable the steering angle of the steerable wheel connected to the first steering actuator to be changed via the second steering actuator,
wherein the electrically operable steering actuators are mechanically coupled to each other by a mechanical coupling comprising a bendable shaft.

2. The steering system as claimed in claim 1 , wherein the bendable shaft has an elasticity of torsion such that a steering angle difference, which occurs during trouble-free operation, between the mechanically coupled steering actuators is compensated for, in the absence of transfer, by the bendable shaft, and a steering angle difference exceeding a usual difference effectuates a transfer of the torque between the mechanically coupled steering actuators.

3. The steering system as claimed in claim 1 , wherein at least one coupling is incorporated into the mechanical coupling of the electrically operable steering actuators, which is open during trouble-free operation of the steering system and is closed in the event of a malfunction.

4. The steering system as claimed in claim 1 , wherein at least one positive-fit coupling is incorporated into the mechanical coupling of the electrically operable steering actuators,
wherein the at least one positive-fit coupling permits a relative motion between its input side and its output side to the extent that a steering angle difference, which occurs during trouble-free operation of the steering system, between the mechanically coupled steering actuators is compensated for, in the absence of transfer, by the at least one positive-fit coupling, and a steering angle difference exceeding a usual difference brings about a positive fit of the at least one positive-fit coupling.

5. The steering system as claimed in claim 4 , wherein at least one spring element is situated between form-fitting elements of the at least one positive-fit coupling, which allows for an elastic positive fit of the at least one positive-fit coupling in such a way that, in the event of a positive fit of the coupling having an increasing steering-angle difference between its input side and its output side, a higher torque is transferred between the mechanically coupled steering actuators.

6. The steering system as claimed in claim 1 , wherein each steering actuator can be disconnected from or connected to the bendable shaft via a coupling.

7. The steering system as claimed in claim 1 , comprising:
at least two steerable front wheels of the vehicle: and
two steerable rear wheels of the vehicle, to each of which a steering actuator is connected for adjusting the steering angle,
wherein all four steering actuators are mechanically coupled to each other via the bendable shaft.

8. The steering system as claimed in claim 1 , wherein each steering actuator comprises a centering spring element which brings each steering actuator into a defined starting position in the event of a malfunction.

9. A method for steering a vehicle, comprising:
providing a steering system as claimed in claim 1 ;
in the event of a failure or a malfunction of a first steering actuator, transferring the steering torque provided by a second steering actuator to the first steering actuator; and
enabling a steering angle of the steerable wheel connected to the first steering actuator to be changed via the second steering actuator.

10. The steering system as claimed in claim 1 , wherein the bendable shaft is flexible.

11. A steering system for a steerable vehicle, comprising:
at least two steerable wheels, each wheel connected to an electrically operable steering actuator to enable each electrically operable steering actuator to adjust a steering angle of a steerable wheel by application of a steering torque,
wherein the electrically operable steering actuators are mechanically coupled to each other such that, in the event of a failure or malfunction of a first steering actuator, the steering torque provided by the second steering actuator is transferred to the first steering actuator, to enable a steering angle of the steerable wheel connected to the first steering actuator to be changed via the second steering actuator,
wherein the electrically operable steering actuators are mechanically coupled to each other for the transfer of a torque from a first steering actuator to a second steering actuator, said steering actuators having a mechanical coupling,
wherein the mechanical coupling has an elasticity of torsion such that a steering angle difference, which occurs during trouble-free operation, between the mechanically coupled steering actuators is compensated for, in the absence of transfer, by the mechanical coupling, and a steering angle difference exceeding a usual difference effectuates a transfer of the torque between the mechanically coupled steering actuators.

12. The steering system as claimed in claim 11 , wherein the mechanical coupling comprises a bendable, flexible shaft.

13. The steering system as claimed in claim 11 , wherein the mechanical coupling comprises a universal joint shaft having at least two rigid shafts that are hingedly connected to each other by a universal joint.

Assignees

• Ford Global Tech Llc
• Thyssenkrupp Presta Ag

Inventors

• Engels Frank Peter
• Polmans Kristof

Classifications

• B62D7/00

  Steering linkage; Stub axles or their mountings (B62D13/00 takes precedence; power-assisted or power-driven steering B62D5/00) · CPC title

• B62D5/003 Primary

  Backup systems, e.g. for manual steering (B62D5/30 takes precedence) · CPC title

• B62D7/148

  provided with safety devices · CPC title

• B62D5/001

  Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup · CPC title

• B62D5/04 Primary

  electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear · CPC title